Firaxis Games has once again raised the bar in the strategy genre with Civilization V, the latest installment in the bestselling turn-based game franchise. This new game introduces hexagon tiles allowing for deeper strategy, more realistic gameplay and stunning organic landscapes for players to explore as they expand their empire. Firaxis also created a new gamestate of the art DirectX 11 graphics engine that orchestrates a spectacular visual experience that brings players closer to the experience than ever before. The game features fully animated leaders interacting with players from a screen-filling diplomatic scene, speaking in their native language for the first time.
Wars between empires feel massive as armies dominate the landscape and combat is more exciting and intense than ever before. The addition of ranged bombardment allows players to fire weapons from behind the front lines, challenging players to develop clever new strategies to guarantee victory on the battlefield. In addition to the new gameplay features debuting in Civilization V, an extensive suite of community, modding and multiplayer elements also makes an appearance.
Having spent the past few decades pushing the strategy gaming genre into new territory with his Civilization franchise, Sid Meier and his team at Firaxis Games weren’t sure about adding another dimension to the gameplay of Civilization V. But they dove into 3D Vision technology, a risky gamble that ended up paying off in the end.
“At first, we were very skeptical about this technology, but after seeing it in action we were surprised at how well it worked for Civ V,” said Dan Baker, graphics lead on the title at Firaxis Games. “I remember the day when Evan (our on-site NVIDIA engineer) worked through the last of the technical issues, and we were ready to show it to everyone at Firaxis. There was such a long line of people waiting to see, and everyone was impressed. It was fun to see Sid Meier sit down and play with it, and watch him get excited about the implications.”
Baker said that 3D Vision makes playing the game feel like you’re interacting with someone’s carefully created model set, with 3D characters bouncing around it in real life.
“The game is much more detailed in 3D vision then than it is in 2D,” explained Baker. “Perhaps this is because you are getting information for each eye, so it’s twice the detail. Strategy games appear to benefit more than the typical FPS would. It’s my belief this is because stereoscopic vision is most useful for things close enough for a person to interact with, e.g., within an arms grasp. With an FPS, most things that the player interacts with are far away, so the 3D experience is limited. For a strategy game, however, it’s more like you are standing over a gameboard, moving pieces around.”
But 3D Vision wasn’t the only technology that Firaxis incorporated into Civilization V. For the last decade, NVIDIA has created a variety of publically available demos and code for various advanced techniques. Baker and his team developed a texture compression system that can decompress itself entirely on the GPU with DX11 class hardware. The leader scenes are over 2 GB of texture data, but fit into a little more than 100 MB. With DX11, they’re able to stream these textures in natively on the GPU, so players will notice almost no load time when entering a leader scene. Firax also used some of the NVIDIA Skin rendering techniques.
“Being one of the flagships of PC gaming, we felt strongly that our Civ V customers wanted us to utilize DX11 hardware appropriately,” said Baker. “Therefore, Civilization V uses both the tessellation feature for terrain, and the compute shader features for the leader scenes. The terrain in Civ V is so dense that if we were to turn it to wireframe while zoomed out, it would appear almost completely solid! By using tessellation, we are able to adapt the number of triangles to avoid wasted triangles. We measured up to a 30 percent increase in performance on DirectX11 hardware. This means that players who have DX11 cards can run the game with most of the options on high, even on mid-range DX11 parts.”
For level based games, it’s common practice to run a high powered lighting solution as a pre-process to give it a more natural and realistic lighting treatment. This process often takes hours, sometimes days just for one level. Firaxis did this for Civilization Revolution, storing several hundred maps on disc, though each map could be slightly randomized.
“For Civilization V, we built a lighting system that could perform the same task on the GPU very quickly, but we needed to store this information,” explained Baker. “To do this efficiently, we used the DXT compression technology from NVIDIA, which allows us to do this compression on the GPU. Thus, for any DX10 and higher video card, we are able to compress and keep most of a very large map in memory. This means that players can scroll around and usually not see the terrain having to page in needed textures.”
Baker and his team worked with NVIDIA from early in the development stage, as the team designed a brand new engine specifically to take advantage of the latest PC technology. NVIDIA even sent an engineer to Maryland to work with the team throughout the game development process.
“At first glance, a lot of people assume that making the graphics engine for a strategy game like Civilization V is easier than an FPS, but in some ways it’s actually harder. Most games on the market today are careful, hand-crafted experiences. This means that the graphics engine knows exactly what it needs to render at any point in time. Each level is carefully built and enemies are carefully placed. Civilization, however, is a user controlled game, where we have to be prepared for all sorts of scenarios. For example, at max zoom in, the player can see around 20 tiles. Each tile can have a unit (with multiple characters), a forest, perhaps buildings, resources, and a few other graphics elements. Zoomed in, this isn’t a huge problem, but when we zoom out, we can see around 500 tiles. Since it is a strategy game, we have to show everything, every frame.”
Although players might not think about it, most strategy games feature hand-made maps. Every map in Civilization V is procedurally created. Baker believes this makes a huge different in replayability, especially since the Civ V engine allows these random maps to appear hand-made.
“Nothing will ever beat the human touch, but random maps are such a huge part of games that we will likely never give them up,” said Baker. “I’m proud of the way we are able to randomly create the terrain. We have one of the best procedural terrain systems ever built. This gives players a unique, rich experience every time they start a new game, giving Civilization V a lot of replayability.”